The VirtualCL (VCL) Cluster Platform

Heterogeneous computing systems can dramatically increase the performance of parallel applications on clusters. Currently, most applications that utilize OpenCL devices (CPUs, GPUs, Accelerators), run their device-specific code only on devices of the same computer were the application runs. This paper presents the VirtualCL (VCL) cluster platform, a wrapper for OpenCL that allows most unmodified applications to transparently utilize many OpenCL devices in a cluster as if all the devices are on the local computer. VCL benefits applications that can use many devices concurrently. Such applications benefit from the reduced programming complexity of a single computer, the availability of shared-memory, multi-threads and lower level parallelism, as in openMP, as well as concurrent access to devices in many nodes, as in MPI. The paper presents the components of VCL and its performance.